NITROUS OXIDE ( nos / n2o ) advice forum

Hi All,

Long time lurker, first time poster, and nitrous newbie. I recently made progress on my project so I thought I would share to inspire/encourage/help others...

Little history: I purchased my 1974 Chevy K10 longbed pick up truck from a friend of mine to tow my ski boat. I no longer use it for towing, so like any good motor head, I started hot rodding it. Over the past few years, I've replaced my stock 1/2 ton driveline with a John Kilgore TH400 full manual transmission, Continental 3000 stall nitrous converter, 14 bolt 9.5 inch rearend with 4.10 gears. the front axle is still a Dana 44, but it's been upgraded with 4.10 gears and a Detroit Locker. All on 35 inch off road tires. It's big, tall, and weighs 5000 lbs. Obviously not an ideal race car, but it's what I have to work with, lol.

About 5 years ago, I started buying nitrous parts from WON and built a 388 Small Bloch Chevy engine in my garage. Due to a new growing family and new business I couldn't find the time to complete or install my nitrous system. Last year, my engine developed a crack in the # 3 cylinder (not nitrous related). Probably due to a .060 overbore on a thin late model block, lesson learned. Again, not having enough time, I dropped it off at a local machine shop/engine builder with the intent of just having the block swapped out and re-using most of my old parts. Well, things got out of control. A new Dart SHP block was ordered along with an upgraded steel crankshaft, connecting rods, .030 Ross forged pistons, ported 2.05 Track 1 Brodix heads, and a bigger custom hydraulic roller camshaft.

At the same time as the new 383 engine was being built, I assembled my WON direct port nitrous system on my Edelbrock Performer RPM dual plane intake manifold. I'm using 8 Crossfire injectors, 4 300hp Quadanoids, Max V2 Race controller, an O2 sensor, nitrous and fuel transducers.

2 days ago the new engine and nitrous system were merged and dyno tested. Note: I eventually plan on running 400+ shot of nitrous on this engine, but I'm moving houses next week, and needed to get my truck up and running. So I played it safe on the dyno and only sprayed a 200 shot of nitrous. Here are the results:
Pump gas engine only: 505hp @ 5600 RPM, 497tq @ 5000 RPM
C-16 gas 100 shot: 622hp @ 5600 RPM, 627tq @ 4100 RPM
C-16 gas 200 shot: 693hp @ 5600 RPM, 717tq @4200 RPM

Overall the system was smooth and engine was happy, but definitely rich. I kept reducing the fuel pressure on my stand alone fuel system. It helped, but I need to order some slightly larger nitrous jets to clean up the tune.

I'd like to say thank you to Trevor for being patient with me and answering all my questions over the course of 5+ years, even the dumb ones! And David and crew at WON for quickly shipping last minute parts to me. Overall, I'm very happy with the product and service. I'll be installing my new engine in the truck in the next few days. I can't wait to put it in 4 wheel low and annihilate my 35 inch tires! I'll eventually find my way over to a drag strip too. I'll let everybody know how it goes

Attached are some recent photos

Dyno sheets...

last photo

That is awesome

Excellent report Scott and it's been a pleasure to assist you to achieve such outstanding results, especially if the mix is still rich.

What fuel pressure did you start with and end up at?

I started with 5.5 lbs. of fuel pressure...Throughout the testing, the engine builder/dyno tuner Guy kept saying "rich is good, rich is safe". He's been building and tuning high performance engines for 20+ years and he drag races cars and boats himself, so I know he knows what he's doing. Once we saw the AFR gauge dip into the low 10's/high 9's, I got uncomfortable and lowered the fuel pressure 1/2 lbs. This slight adjustment caused the AFR to stay out of the 9's and pushed it up to high 10's. Attached is the last dyno pull after lowering the fuel pressure. Torque went up slightly and horsepower went down slightly...

Guy recommended to not lower the fuel pressure any lower than 5 lb. He thought it's best to install slightly larger nitrous jets to clean up the tune and get the AFR into the high 11's. What do you recommend? What's a safe AFR reading? Keep in mind, I'm not trying to squeeze every last horsepower out of this engine. Don't want to be on the "edge". Just looking for a happy engine that will live a long time...Do you sell 51, 52, or 53 jets? Or is the next jet size up a 75?
Thanks!
Scott

Lovin this build and I hope the finished product comes soon. Also, kudos on the choice for the quadrinoid: it's a much cleaner setup.

Thanks Goyle and Turbobox...Just following Trevor's advise

Trevor, I'm running # 50 jets in the nitrous and fuel. I'll talk to Dave to find out exactly what jets are available. Should I install the next nitrous jet size up (55 or 60), leave the fuel jet at 50, then adjust the fuel pressure up as necessary? Or because I have the Max V2 Race controller with O2 sensor, can I set the controller to hold a certain AFR reading, like 12.0? Will the Maz V2 Race pulse the Quadanoids appropriately to create a certain AFR reading?

Scott

Trevor,

For my stand alone (nitrous only) fuel system, I'm currently running a Holley Red electric fuel pump, specs:

Brand: Holley
Manufacturer's Part Number: 12-801-1
Part Type: Fuel Pumps, Electric External
Product Line: Holley Red Electric Fuel Pumps
Free Flow Rate: 97 gph
Maximum Pressure (psi): 7 psi, this pump flows 67 gph at 5 psi
Inlet Size: 3/8 in. NPT
Inlet Quantity: One
Inlet Attachment: Female threads
Outlet Size: 3/8 in. NPT
Outlet Quantity: One
Outlet Attachment: Female threads

Scott

That's a difficult one to call, as you don't have much additional pressure to work with. I think I'd go for the next size up on nitrous jet whether it's 55s or 60s but if you don't mind buying 2 sizes, I'd go for the next 2 sizes, to be sure you have it covered.

Thanks, I'll order 2 set of larger nitrous jets shortly...Worst case, I can replace my existing fuel pump with bigger more powerful one capable of more pressure.

Scott